The US is to protest to the Turkish prime minister for comments he made calling Zionism a crime against humanity.
Secretary of State John Kerry is meeting Prime Minister Recep Tayyip Erdogan in Ankara today and plans to take him to task for "particularly offensive" comments.
An official on board Mr Kerry's plane as he flew from Rome, said the Obama administration was profoundly concerned by and disappointed in Mr Erdogan's remark at a UN conference in Vienna.
Outrage over the remarks threatens to overshadow Mr Kerry's visit to Nato ally Turkey on his first official overseas trip as secretary of state. He has spent much of his time at the first three stops focusing on the conflict in Syria.
Mr Erdogan said in Vienna that Islamophobia ought to be considered a crime against humanity "just like Zionism, anti-Semitism and fascism".
Israeli Prime Minister Benjamin Netanyahu sharply condemned the statement calling it "dark and mendacious".
US National Security Council Spokesman Tommy Vietor said the characterisation was "offensive and wrong" and said people of all religions should "denounce hateful actions and overcome ... differences".
Mr Erdogan's ruling party has roots in Turkey's Islamic movement.